net: Make qdisc_skb_cb upper size bound explicit.

BugLink: http://bugs.launchpad.net/bugs/954576

[ Upstream commit 16bda13d90c8d5da243e2cfa1677e62ecce26860 ]

Just like skb->cb[], so that qdisc_skb_cb can be encapsulated inside
of other data structures.

This is intended to be used by IPoIB so that it can remember
addressing information stored at hard_header_ops->create() time that
it can fetch when the packet gets to the transmit routine.

Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

3 files changed, 3 insertions, 6 deletions

diff --git a/net/sched/sch_choke.c b/net/sched/sch_choke.c
index 06afbaeb4c8..178ee83175a 100644
--- a/net/sched/sch_choke.c
+++ b/net/sched/sch_choke.c
@@ -225,8 +225,7 @@ struct choke_skb_cb {
 
 static inline struct choke_skb_cb *choke_skb_cb(const struct sk_buff *skb)
 {
-        BUILD_BUG_ON(sizeof(skb->cb) <
-                sizeof(struct qdisc_skb_cb) + sizeof(struct choke_skb_cb));
+        qdisc_cb_private_validate(skb, sizeof(struct choke_skb_cb));
         return (struct choke_skb_cb *)qdisc_skb_cb(skb)->data;
 }
 
diff --git a/net/sched/sch_netem.c b/net/sched/sch_netem.c
index 69c35f6cd13..87b965811c2 100644
--- a/net/sched/sch_netem.c
+++ b/net/sched/sch_netem.c
@@ -117,8 +117,7 @@ struct netem_skb_cb {
 
 static inline struct netem_skb_cb *netem_skb_cb(struct sk_buff *skb)
 {
-        BUILD_BUG_ON(sizeof(skb->cb) <
-                sizeof(struct qdisc_skb_cb) + sizeof(struct netem_skb_cb));
+        qdisc_cb_private_validate(skb, sizeof(struct netem_skb_cb));
         return (struct netem_skb_cb *)qdisc_skb_cb(skb)->data;
 }
 
diff --git a/net/sched/sch_sfb.c b/net/sched/sch_sfb.c
index 0a833d0c1f6..47ee29fad35 100644
--- a/net/sched/sch_sfb.c
+++ b/net/sched/sch_sfb.c
@@ -93,8 +93,7 @@ struct sfb_skb_cb {
 
 static inline struct sfb_skb_cb *sfb_skb_cb(const struct sk_buff *skb)
 {
-        BUILD_BUG_ON(sizeof(skb->cb) <
-                sizeof(struct qdisc_skb_cb) + sizeof(struct sfb_skb_cb));
+        qdisc_cb_private_validate(skb, sizeof(struct sfb_skb_cb));
         return (struct sfb_skb_cb *)qdisc_skb_cb(skb)->data;
 }